Foundry sand forming machines



July 4, 1967 R. w. ELLMS FOUNDRY SAND FORMING MACHINES 5 Sheets-Sheet 1Filed Oct. 16, 1964 INVENTOR. ROBERT W. ELLMS BY agd.omaz

A TTORNEYS July 4, 1967 R. w. ELLMS 3,328,852

FOUNDRY SAND FORMING MACHINES Filed 0012. 15. 1964 5 Sheets-Sheet 2INVENTOR. ROBERT W. E LLMS flmmgaameg ATTORNEYS July 4, 1967 R. W. ELLMSFOUNDRY SAND FORMING MACHINES Sheets-Shet 4 Filed Oct. 16, 1964 xmOuxmOm

mEFm mmOO m. 0 mQIO mosmmad 02E 10km INVENTOR. ROBERT W. ELLMS dlhiz/flwq 6311114211?! A TTOENEYS July 4, 1967 R. w. ELLMS FOUNDRY SAND FORMINGMACHINES 5 Sheets-Sheet 5 Filed Oct. 16, 1964 INVENTOR. ROBERT W. ELLMSATTORNEYS United States Patent 3,328,852 FOUNDRY SAND FORMING MACHINESRobert W. Ellms, North Olmsted, Ohio, assignor to The OsbornManufacturing Company, Cleveland, Ohio, a corporation of Ohio Filed Oct.16, 1964, Ser. No. 404,397 19 Claims. (Cl. 164-401) This inventionrelates generally as indicated to foundry sand forming machines and moreparticularly to automated foundry mold and core making machines.

In foundry molding machines, a vertically movable table is generallyemployed to assemble a pattern and flask which may be elevatedconventionally by a hydraulic ram to an intermediate position at whichthe flask is filled with sand, struck ofi, jolted, etc., and thenfurther moved upwardly against a squeeze head to ram the sand within theflask. The table is then lowered stripping the pattern from the mold andthe formed mold within the flask is then moved to a core setting, moldclosing and finally a pouring station. If the sand is to be blown withinthe flask, the table is still stopped at an intermediate position forthe flask filling operation and when completed is then moved againupwardly to squeeze the sand within the flask against a squeeze head.Reference may be had to US. Patent No. 3,089,207 to L. F. Millerillustrating an exemplary type of hydraulically operated blow andsqueeze foundry molding machine.

In core forming machines, a similar intermediate position is oftentimesrequired in the vertical stroke of a table or cradle supportingseparable cope and drag parts of a mold box which is elevated against ablow head for introduction of sand within the box. The box may be heatedto cure the resin-sand mix and is generally lowered away from thesqueeze head to an intermediate position to permit a heating and punchout head to be placed thereover and after the core is sufficientlycured, the table or cradle is then lowered further to disassemble themold box and strip the core therefrom.

While vertically intermediate precise positions are fairly easy toobtain with hydraulic equipment, because of the masses and short timecycles involved, such positioning of the mold box or flask is not aseasily obtainable with pneumatic systems. More and more machinerymanufacturers are switching to pneumatic operation of machinery becauseof the complexity and expense involved in hydraluic machines. Mechanicalstops or latches limiting the strokes of large size pneumatic pistonsmay be provided, but these are subject to wear during repeated operationand are not sufliciently foolproof to obtain the desired degree ofautomation. Moreover, intermediate positioning devices must be able totake substantial stresses in view of the masses and movements involvedas well as shock loads which may result from the jolting, sand filling,and like operations performed at such intermediate positions.

It is accordingly a principal object of the present invention to providea simplified intermediate positioning device for foundry sand formingmachines.

Another object is the provision of a pneumatically operated stop ringfor use in foundry sand molding and core blowing machines by which anintermediate operational position can be obtained.

A further object is the provision of automatic sand forming machines forfoundries and the like providing fluid pressure operated stop means forpositioning and supporting sand containers.

Yet another object is the provision of automated pneumatically operatedfoundry mold and core making machines of a simplified constructionobtaining a high degree of reliability.

Other objects and advantages of the present invention will becomeapparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andthe annexed drawings setting forth in detail certain illustrativeembodiments of the invention, these being indicative, however, of but afew of the varous ways in which the principles of the invention may beemployed.

In said annexed drawings:

FIG. 1 is a front elevation partially broken away and in section of acore blowing machine in accordance with the present invention;

FIG. 2 is an end elevation of such machine partially broken away and insection as seen from the right in FIG. 1;

FIG. 3 is an enlarged fragmentary detail view partially broken away andin section of the pneumatic intermediate stop mechanism;

FIG. 4 is a schematic pneumatic operational diagram of the machineillustrated in FIGS. 1 through 3;

FIG. 5 is a fragmentary vertical section of a foundry molding machineillustrating the employment of a similar pneumatic stop mechanism; and

FIG. 6 is a schematic pneumatic operational diagram illustrating theoperation of the stop mechanism shown in FIG. 5.

Core blowing machine Referring first to FIGS. 1 and 2, there isillustrated a core blowing machine constructed in accordance with thepresent invention which comprises a base frame 1 on which are supportedfour columns 2, 3, 4 and 5 at each corner of the machine. The base frame1 includes a depending cylinder 6 housing a large clamp piston 7, thereduced diameter tubular rod 8 of which supports table 9 for verticalmovement.

Mounted on the columns 2 through 5 is a head 12 which is secured to suchcolumns and to the base frame 1 by means of elongated tensioning members13 illustrated in FIG. 1. The top frame or head 12 includes a verticallyextending passage 15 seen in FIG. 2 which branches and is connected toblow valve 16 and exhaust valve 17 mounted on the top of the machine.The lower end of the passage 15 extends through blow head frame 18 whichis provided with a peripheral seal indicated at 19. Each of the posts 2through 5 is provided with brackets 21 on the inner sides thereofsupporting horizontally extending parallel rails 22 and 23. Such railssupport tandemly arranged reservoir and manifold carriages 25 and 26which are interconnected by links 27. The carriages are supported on therails by means of rollers 28 having V-shaped grooves therein which aremounted in carriage wheel brackets 29. Such brackets and supportingrollers are mounted at the corners of each carriage and support the samefor horizontal shuttling movement along the rails 22 and 23. Thereservoir carriage 25 supports cylindrical sand reservoir 30 havingfrusto-conical bottom portion 31 terminating in blow plate 32 which maybe provided with a series of blow openings 33 through which the sandwithin the reservoir is discharged. As indicated at 35, the wall of thecylindrical and frusto-conical portions of the reservoir may 'bejacketed so that a cooling fluid such as water may be circulated aboutthe reservoir to maintain the sand-resin mix therewithin at the propertemperature to prevent premature cure. Covers 36 to access ports in thefrusto-conical portion 31 may be provided for cleaning the interior ofthe reservoir. The interior cylindrical portion 37 of the reservoirextends upwardly through the carriage 25 and may be brought intoregistry with the ring 18 and seal 19' communicating with the passage15. Normally, the top of the carriage is provided with. adequateclearance to shuttle to and from a position in registry with the blowopening in the head 12.

Such shuttling movement is obtained by a pair of piston-cylinderassemblies 40 which may be mounted on trunnion blocks 41 on brackets 42at the left side of the head 12 seen in FIG. 1 and the rods 43 thereofare connected at 44 to bracket plates 45 secured to the reservoircarriage 25. In this manner, the shuttling movement of the reservoircarriage and through the link 27, the manifold carriage 26, is obtained.When the pistoncylinder assemblies 40 are retracted, the upwardly opencylindrical interior 37 of the reservoir will be positioned beneathhopper 47 which may be connected to a sand supply, not shown. The hopper47 includes a chop gate 48 which is pivoted at its top to shaft 49 whichhas secured thereto link 50 connected at 51 to the rod ofpiston-cylinder assembly 52. The assembly 52 is mounted on a trunnionblock 53 mounted on the end of the head frame 12 shown broken away inFIG. 1. It can now be seen that extension of the assembly 52 will causethe chop gate 48 to pivot about the shaft 49 to open and close thehopper to drop or dispense the resin-sand mix therewithin into thereservoir 30 when positioned vertically in registry therewith.

Such registered position will be obtained when the piston-cylinderassemblies 40 retract the reservoir 30 to the fill position beneath thehopper 47. In such position, the manifold carriage 26 will then bepositioned directly vertically above the table 9. The manifold carriage26 includes vertically extending side plates 54 and 55 which support abottom plate 56 on which is mounted a vertically extending pneumaticcylinder 57, the rod of which is connected to manifold adapter plate 58and guide rods 59 mounted in bushings 60 assist in the alignment andguiding of the plate 58 for vertical movement. An adapter frame 61 issecured to the bottom of the adapter plate. To the frame 61 will beattached a heating and punch out mechanism which may include a gasmanifold for the cope portion of the mold box as well as verticallyextending plates or pins adapted to clean the apertures in the top ofthe cope and facilitate the stripping of the blown core from the cope.The configuration of the heating and punch out mechanism, which ismounted for vertical movement on the manifold carriage 26 by means ofthe vertically extending piston-cylinder assembly 57, will varyaccording to the customers requirements and, of course, according to theparticular sand cores being formed. In any event, it is apparent that asthe reservoir 30 is moved from the blow poistion illustrated in FIG. 1to the fill position beneath the hopper 47, the heating and punch outhead carried by the manifold carriage 26 will then be positionedvertically above the table 9. An illustrative form of the manifold andpunch out pins are shown in phantom lines at 62 in FIG. 1.

The cope portion C of the mold box is also shown in phantom lines and isnormally supported on brackets 63 secured to the posts 2 through 5. Suchbrackets may include locating pins 64 seen in FIG. 2 on which the copeis precisely positioned and supported. The lower half of the mold box ordrag D may be supporteddirectly on the table 9.

In operation, the table 9 will be elevated to cause the drag D to engagethe cope C to lift the latter from the locating pins 64 to form the coreor mold enclosure and then the enclosure is further elevated to clampthe same against the blow plate 32, which when the reservoir is in theposition shown in FIG. 1, will be aligned with the blow ring 18. Thevertical movement of the table may actually lift the reservoir and itscarriage from the rails 22 and 23 to clamp the reservoir against theseal ring 19. The mold enclosure comprised of the cope and drag and thereservoir will then firmly be clamped together. After the sand is thenblown within the core box thus formed, the reservoir must be unclampedto permit the same to be shifted laterally to a fill position beneaththe hopper and the manifold carriage 26 to be positioned thereabove. Inorder to accomplish this, the table 9 must be lowered to an intermediateor cure position but not far enough to cause the cope to engage thesupporting pins 64 and thus start to separate the mold halves. It is, ofcourse, extremely difficult to position precisely the table 9 by meansof the large pneumatic piston 7. To accomplish this precise intermediatepositioning of the table, there is employed a stop ring 65 surroundingthe piston rod 8 within the top of the cylinder 6.

Referring now more particularly to FIG. 3, it will be seen that thecylinder 6 is provided with a top flange 66 seated on annular support 67in the base frame 1. The flange 66 supports annular cap 68, the top ofwhich surrounds annular guide 69 for the clamp piston rod 8. Theinterior of the cap 68 is provided with a cylindrical guide surface 70sl'idingly confining the annular top 71 of stop ring 65. The stop ring65 includes a downwardly extending cylindrical portion 72 having anannular shoe 73 forming an abutment to engage the top surface 74 of theclamp piston 7. A stop ring 75 is secured to the lower end of the cap 68within the cylinder wall 6 and the inwardly projecting shoulder formedby the ring 75 serves to engage the top or piston portion 71 of the ring:65 limiting vertical movement thereof. Such piston portion 71 isprovided with a piston ring 76 and the upper outer edge thereof isrecessed as indicated at 77 and such recess is in communication withtapped air passage 78 in the wall of cap 68. A vent passage 79 isprovided in the cap 68 and may serve to vent both the upper end of theclamp piston 7 as well as the lower end of the piston portion 71 of thestop ring 65.

It can now be seen that the clamp piston 7 can be driven down to theintermediate position simply by pressurizing the air passage 78 at highpressure causing the abutment or shoe 73 of the ring 75 to engage thetop surface 74 of the clamp piston 7 to drive the same downwardly. Airunder low pressure beneath the clamp piston will maintain the surfaces73 and 74 together with the piston portion 71 in engagement with thering 75.

Further describing the core blowing machine embodiment of the presentinvention, it will be seen in FIG. 1 that the table 9 includes avertically extending guide rod 80 extending through bushing 81 to keepthe table 9 from rotating Within the cylinder 6 and to maintain the copeand drag of the mold box in precise vertical alignment.

After the intermediate position is achieved and the cores have beencured sufficiently to strip from the mold box, the air pressure beneaththe clamp piston 7 is vented and the table 9 descends to deposit thecope C on the supporting brackets and the stripping pins within theheating and punch out head shown in phantom lines at 62 may assist incleaning the apertures in the cope and stripping the core therefrom, Thecores now within the drag D or bottom half of the mold box will thendescend and stripping pins may then be employed to cause the cores anddrag to separate. The pins may be mounted for vertical movement withrespect to the drag by piston-cylinder assemblies or the pins may becaused to engage fixed abutments so that the drag will be loweredtherepast to cause the cores to be elevated above the top of the drag.The drag too may be provided with a heating manifold and in order toremove the cores from the machine, a plurality of pickoif fingers 84 maybe employed to move beneath the cores and withdraw the same from themachine. Such pick-off fingers are mounted on a head frame 85 pivoted at86 to vertically extending pivot bracket 87 mounted on carriage 88. Thecarriage 88 may be provided with top and bottom rollers 89 at each endthereof which confine therebetween rail 90. A link 91 is pivoted at 92to the carriage and at its opposite end to one arm of bell crank 93. Theopposite end of the bell crank is pivoted at 94 to the frame and thecrank 93 may be pivoted about the pivot 94 by means of thepistoncylinder assembly '96 which is mounted on trunnion block 97. Therod 98 of the assembly 96 is pivoted at 99 to the crank 93. Accordingly,when the assembly 96 is retracted, the carriage 88 is caused to movealong the rail 90 to advance the fingers 84 into the machine beneath thecores. Conversely, when the assembly 96 is extended, the carriage 88 iscaused to move along the rail 90 to retract the fingers 84 from themacine.

The fingers 84 may be raised and lowered by means of a piston-cylinderassembly 100 mounted on the carciage 88, the rod of which is connectedat 101 to link 102. The proximal end of the link 102 is pivoted at 103to the carriage 88 and directly therebeneath is a parallel link 104pivoted at 105 to the carriage and at 106 to the bottom of thevertically extending portion 87 of the bracket supporting the fingerframe 85. The vertically extending portion 87 is also pivoted at 107 tothe link 102 so that the pivots 103, 105, 107 and 106 form a parallellinkage to raise and lower the fingers 84 at the direction of thepiston-cylinder assembly 100, all of the linkages as well as theassembly 100 being mounted on the carriage 88 for movement with thefingers into and out of the machine.

In addition, the fingers 84 may be tilted about the horizontal axis ofthe pivot 86 by means or piston-cylinder assembly 110 seen more clearlyin FIG. 1, the rod of which is pivoted at 111 to the frame 85 and thecylinder may be mounted on bracket 112 connected to the carriage. Inthis manner, an operator standing to the side of the finger mechanismmay receive the blown cores withdrawn from the machine moreconveniently. The various linkages on the carriage may be mounted in aprotective housing 113 supported on frame members 114 extending from thehorizontal support frame 95 extending laterally from the machine.

Core blowing machine-opemti0n-FIG. 4

Referring now to FIG. 4, the operation of the core blowing machineembodiment of the present invention may be electric and pneumatic andoperated through a complete cycle in a completely automatic manner. Airmay be supplied from a plant source to a filter and a line lubricator121 from which air passes through a manually operated lock-out valve 122to valve inlet manifold 123. A branch line 125 between the lubricatorand filter leads to a pressure regulating valve 126 leading to airstorage tank 127. The storage tank 127 is connected to the blow valve 16which is in turn connected to the reservoir 30 when the carriage 25 isin position beneath the blow head. The air storage tank 127 is alsoconnected to the exhaust valve 17 through a two-way poppet valve 128which is in turn controlled by a mechanically operated reservoir safetyvalve 129.

Parallel to the inlet header 123 is an exhaust header 131 and connectedto the parallel headers are the function control valves. The top valve132 is a single solenoid valve which may be employed to cause the tableto elevate upon the energization of the associated solenoid. Air issupplied from the inlet header 123 to the line 133 to poppet valve 134which is then shifted to open line 135 which may be connected at 136 tothe air supply for providing filtered and lubricated air to the variouspoppet valves. The wall of the cylinder 6 may be provided with twoinlets, one slightly above the other and the upper may be slightlylarger as compared to the lower. For example, the upper may be a 2-inchinlet, while the lower is a /2-inch inlet. A flow control valve 136 isconnected to the lower inlet and a pressure gauge 137 as well aspressure switches 138 and 139 are also provided connected to the lowerinlet.

The pressure switch 138 may be employed to indicate the full clamppressure being obtained so that the blow operation may commence. Thepressure switch 139 is preset for a specified range and may be employedto control solenoid valve 140 supplying air through line 141 to twowaypoppet valve 142 so that air supplied through line 144 from source 136through three-way poppet valve 145 will force the stop ring 65downwardly pushing the piston 7 downwardly to the intermediate or cureposition. The three-way poppet valve 145 is controlled by solenoid valve147 supplying air through line 148 to the poppet. In this manner, thetable 9 is held at an intermediate cure position while still supportedon a relatively large volume of air. The cure position must be preciselymaintained especially if additional heating equipment such as arbors areemployed which project laterally into openings within the core box.

The clamp pressure switch 138 signals the blow control valve 150supplying air through line 151 and venting line 152 opening the blowvalve 16 while closing the exhaust valve 17. The carriage 25, 26 iscontrolled through double solenoid valve 153 operating three-way poppetvalves 154 and 155 to supply air selectively to the rod and blind endsof the carriage cylinder assemblies 40 through the flow control valvesillustrated. The chop gate 48 may be operated directly from the doublesolenoid valve 156 which causes the piston-cylinder assembly 52 toextend and retract, The cope strip cylinder assembly 57 on the carriage26 is actuated by double solenoid control valve 158 which actuatespoppets 159 and 160 retracting and extending, respectively, the assembly57. Double solenoid control valve 161 is employed directly to actuatethe cylinder assembly 110 tilting and untilting the core fingers 84while the double solenoid valve 162 is employed directly to operate theassembly 100 to raise and lower the fingers. The double solenoid valve163 is employed to advance and retract the fingers 84 by actuating thepoppet valves 164 and 165, respectively, supplying air to the rod andblind ends of the assembly 96 through the flow control valvesillustrated.

An automatic cycle of the machine would start with the table or clampcylinder in its lowermost position and with the fingers 84 retracted.The carriage with a reservoir charged with sand would be extended sothat the reservoir is in the blow position shown in FIG. 1. With themachine in such condition, the table 9 is then elevated by the valve 132and at the same time the retracted fingers 84 may be tilted by thecylinder assembly 110 so that the operator may remove the previouslyblown cores from the machine. The piston 7 continues upwardly toassemble the drag portion D with the cope portion C of the mold boxlifting the latter from the support and aligning pins on the frame tomove the now assembled mold box against the blow plate 32 of thereservoir 30. During such movement, the piston 7 will elevate the stopring assembly 65 with the poppet valve 145 positioned to exhaust airfrom the cylinder wall 70 through port 78. Continued upward movement ofthe clamp piston will engage the reservoir and the mold box lifting theformer from the rails 22. and 23 seating the same against the blow head.The pressure switch 138 will then actuate the blow valve 150 to blow thesand from the reservoir into the mold box. The valves 140 and 147 arethen actuated and with the aid of the pressure switch 139 the stop ring65 will engage the top of the piston 7 to lower the table to theintermediate cure position. A limit switch signalling that the table hasachieved the intermediate cure position will then start the time curecycle and also energize the valve 153 to retract the assemblies 40moving the carriages 25 and 26 to the fill position. In such position,the carriage 26 will move the cope cure and punch-out head above the nowlowered mold box. When the carriage is at the fill position, a limitswitch will open the chop gate 48 through the valve 156 and may alsoprepare the cope strip piston-cylinder assembly 57 to be actuatedthrough the valve 158. When the cure cycle is complete, the chop gate 48will be closed and the piston-cylinder assembly 110 may again beactuated to bring the fingers 84 to a horizontal position. The table 9is now lowered to separate the cope from the drag and the cores willremain in the drag as the table is lowered. Stripping fingers eitherfixed or vertically movable may then elevate the cores above the dragand when the table is in its lowermost position, being cushioned by theflow control valve 136, the fingers 84 are then advanced by retractionof the piston-cylinder assembly 96 at the direction of the valve 163, Atthe same time, the cope strip assembly 57 may be retracted and thecarriage indexed to its blow position with the reservoir verticallyabove the table. The valve 162 is then actuated to elevate the fingers84 to raise the same from the stripping pins and the valve 163 may thencause the piston-cylinder assembly 96 to extend retracting the fingers84 and thus the cores from the machine.

Molding machine Referring now to FIGS. and 6 and first to FIG. 5, thereis illustrated the base section of a foundry molding machine whichincludes a base frame 170 provided with four upstanding posts 171 at thecorners thereof which may supoprt a sand hopper, measuring box, and ashuttling carriage including a squeeze head and a sand chute. Referencemay be had to the copending application of Leon F. Miller et al., SerialNo. 252,644, filed January 21, 1963, entitled Molding Machine, nowPatent No. 3,205,542, for an illustration of a similar but hydraulictype of foundry molding machine utilizing foundry flasks which aretrundled to and from the machine for the jolting and ramming of foundrysand therewithin.

The base frame 170 supports therewithin a large cylinder 172 whichincludes top and bottom rings 173 and 174 and a bottom membr 175 closesthe lower end of the cylinder. The bottom closure 175 may be providedwith an air inlet as indicated at 176. The top of the cylinder 172 isprovided with a cap 177 which may be secured to the top of the cylinderby suitable fasteners 178. Soft copper or like material gaskets may beprovided at 180 and 181 to provide a sealed cylindrical enclosure forthe main squeeze piston 183. Projecting upwardly from the main piston183 is a cylinder 184 which may be secured to the piston by thefasteners indicated at 185. A peripheral top flange 186 is mounted onthe top of the cylinder 184 and may be secured thereto by the fasteners187. Reciprocably mounted within the cylinder 184 is a shockless rampiston 190 supported on heavy duty coil spring 191. The ram piston 190includes an upstanding cylindrical portion 192 which receives thereinthe depending jolt piston 193 secured to the table 194 which in turnsupports pattern stool 195 on which the pattern plate and pattern willbe positioned,

The cylinder 184 then constitutes a hollow piston rod for the squeezepiston 183 while the cylindrical portion 192 of the shockless ram piston190 constitutes the cylinder for the jolt piston 193 on which the tableis mounted,

For a more clear disclosure of a similar shockless jolt mechanism,reference may be had to the copending application of Robert W. Ellms,entitled Molding Machine, Ser. No. 322,405, filed Nov. 8, 1963.

Air for the jolting operation is supplied through line 197, verticallyextending passage 198 in the jolt piston 193, by-pass porting passage199 in the cylindrical portion 192 of the ram piston 190, and finallyvertically extending passage 200 in the jolt piston 193. When air issupplied through such passages to the chamber 202 between the ram andjolt pistons 190 and 193, the latter will be caused to elevate and theformer will be driven downwardly against the spring 191. Such movementwill continue until the exhaust passage 203 is opened at which time theby-pass passage 199 will block communication between the passages 198and 200. The exhaust passage 203 communicates with vertically extendingpassage 204 in the ram piston 190. Such vertical passage is incommunication with the chamber 205 beneath the ram piston 190 and thejolt exhaust air passes out through the top port 206. The exhaust escapepassage 204 may be restricted to cause an increase in the pressure inchamber 205 beneath the ram piston 190 and this pressure may 8 assistthe spring 191 in driving the ram piston upwardly. Simultaneously, dueto the jolt air being exhausted, the jolt piston 193 starts to descendgravitationally and the two meet at 207 causing the jolt action.

However, prior to such jolt action, the table 194 must be elevated topick up a flask so that the same will enclose the pattern supported onthe stool 195, such flask usually being conveyed into the machine on aroller conveyor. The thus elevated flask and the pattern therewithinform the mold box and sand must then be placed therein. To do this, themain squeeze piston 183 must be elevated to assemble the flask andpattern and support the former above the roller conveyor for the fillingand jolting operation. If the machine utilizes a horizontally shuttlingsqueeze head, such must be shuttled into position above the flask whilethe latter is supported in its intermediate position and furtherelevation of the squeeze piston 183 will then ram the sand within theflask against the squeeze head.

In order to obtain the precise intermediate positioning required in thepneumatic molding machine illustrated, a stop ring 210 is employed whichis similar in purpose and configuration to the stop ring 65 in the FIG.3 core blowing machine embodiment. The stop ring 210 includes acylindrical rod portion 211 and a piston portion 212 at the bottomthereof provided with a sliding seal 213 in engagement with the interiorof the main cylinder 172. The cylindrical rod portion 211 of the ring210 is fitted between the exterior of the cylindrical rod 184 of thesqueeze piston 183 and ring 215 mounted on shoulder 216 on the interiorof the cap 177. A chevron type gland 217 may be provided, the top ofwhich is confined by L-shape ring 218 secured by fasteners 219 to thetop of the cap 177. The upper portion of the cylindrical rod 211 isprovided with a ring 220 which serves as an abutment limiting verticalmovement of the stop ring 210. A shelf 221 is provided on the ringabutment 220 and flexible boots 222 and 223 extend above and below theshelf, respectively, to protect the sliding parts of the machine fromdust and dirt. An air inlet 225 is provided in the cap 177 communicatingwith the chamber 226 above the stop ring piston 212 and a vent passage227 on the interior of the cylindrical rod portion 211 of the stop ring210 is provided for the annular chamber 228 formed by the cylinders 184and 172 between the pistons 212 and 183.

Molding machineoperati0n Referring now to FIG. 6, it will be seen thatair may be supplied from a suitable source 230 through a manuallyoperable lock-out valve 231 to air line 232 from which branches 233,234, 235 and 236 extend. The latter is connected to a plug-in typesingle solenoid pilot operated four-way valve 237 which includes asolenoid operated valve 238, a manual override valve 239, and twopositional directional valve 240 operated thereby to supply airselectively to the line 197 connected to the table 194 to provide thejolt action.

The line 235 is provided with a filter 242, an air pressure regulator243, and a line lubricator 244.. From the lubricator, the air passes toplug-in type double solenoid pilot operated four-Way valves 245 and 246,each of which may include solenoid valves 247 and 248 and manualoverride valves 249 and 250, respectively, pilot operating two-positiondirectional valve 251. The valve 245 operates poppets 252 and 253 inlines 233 and 234,

respectively, and the valve 246 operates poppets 254 and 255 in line 234and exhaust line 256, respectively.

Air may also be supplied from source 258 through lock-out valve 259 toline 260. Such line may be provided with a pilot regulator 261 and apilot operated pressure regulator 262 as well as a check valve leadingto an air receiver 264 for air at about 40 p.s.i., for example. Thereceiver 264 is connected to the poppet 253 and thus selectivelyconnectible to the line 234 beyond such poppet. The line 234 passingthrough the poppets 253 and 254 is 9 connected to the main cylinder 172through the illustrated ports 266 and 267, the lower being the smallerof the two and may be connected to the passage 172 illustrated in FIG.5. Pressure switches 268 and 269 are connected to the lines 233 and 234,respectively, sensing the respective pressures above the stop ringpiston 212 and beneath the squeeze piston 183. The poppets 252, 254 and255 are each provided with exhaust mufliers as seen at 270.

The cycle of operation will, of course, start with the table in thelowermost position and when in such position, the flask will be trundledabove the pattern supported on the plate upon the stool 195. Now toelevate the table, the valve 246 may be actuated to close the ex haustpoppets 254 and 255 so that air will enter beneath the squeeze piston183 through the line 260 and the 40 psi. air receiver 264. With thepoppet 252 in the position shown, air will be supplied to the top of thestop ring piston 212 through the line 233 which may be connected to thesource 230 which may be at regular plant line pressure at approximately100 p.s.i. The higher pressure behind the piston 212 will thus provide apositive stop for the squeeze piston 183 as it moves upwardly to elevatethe flask from the conveyor rolls or like equipment. In suchintermediate position, sand will then be placed within the flask, struckoff, optionally jolted, and a squeeze head may then be positionedvertically above the flask. At the completion of the jolting operationand when the squeeze head is properly positioned, the valve 245 may thenbe employed to reverse the poppets 252 and 253 now venting the chamberabove the stop ring piston 212 and supplying regular high pressure plantair to the bottom of the squeeze piston 183. Pressure may continue to bebuilt up to the desired degree regulated by the switch 269 at which timethe valve 246 may be reversed venting the main squeeze piston. Thepressure switch 268 may be employed to signal the required stoppingpressure behind the stop ring piston 212 permitting the elevating of thetable and thus the cycle of operation to commence. It will, of course,be appreciated that the jolting action can be employed simultaneouslywith the further elevation of the table during the squeeze operation.But in any event, the table requires to be positioned precisely in anintermediate position for the flask filling and squeeze head shuttlingoperation.

As the table descends, the flask with the formed mold therein will bedeposited on the conveyor mechanism for trundling from the machine andthe pattern Will be stripped therefrom upon further lowering of thetable.

It can now be seen that there is provided pneumatic sand forming foundrymachines whereby an intermediate position of the table or support isprecisely conveniently obtained 'by differential forces acting upon themain clamp or squeeze piston and the stop ring. In the illustratedembodiments, the differential forces are obtained by differentialpressures and such forces are, of course, dependent on the areas overwhich such pressures are applied. Because of the much larger area of theclamp or squeeze piston, only a relatively slight increase in pressureis required to overcome the force exerted by the smaller stop ring toelevate the table or support there beyond. Pressure variations can beobtained in many ways and those illustrated are considered simply to beexamples which might conveniently be employed with the two types ofmachines illustrated.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

I, therefore, particularly point out and distinctly claim as myinvention:

1. A core blowing machine comprising a vertically movable table adaptedto support a drag portion of a mold box, a piston rod extending fromsaid table having a main clamp piston thereon, a cylinder surroundingsaid main clamp piston, means to supply air under pressure directedsingle acting pistons, and means to vary the pressures acting thereon toachieve such intermediate position.

3. A core blowing machine as set forth in claim 2 including a commonexhaust passage for said pistons.

4. A core blowing machine comprising a vertically movable table adaptedto support a drag portion of a mold box, a piston rod extending fromsaid table having a main clamp piston thereon, a cylinder surroundingsaid main clamp piston, means to supply air under pressure beneath saidpiston to elevate said table to assemble such drag portion with a copeportion and clamp the thus formed core box against a sand reservoir, astop piston surrounding said rod above said main piston, means limitingvertical movement of said stop piston, means operative to energize saidstop piston to drive said main piston downwardly to a predeterminedintermediate position, said main and stop pistons comprising oppositelydirected single acting pistons, means to vary the pressures actingthereon to achieve such intermediate position, a common ex-haust passagefor said pistons, a depending annular shoe on said stop piston operativeto engage said main piston, and a shoulder ring limiting verticalmovement of said stop piston but clearing said annular shoe.

5. A core blowing machine comprising a vertically movable table adaptedto support a drag portion of a mold box, a piston rod extending fromsaid table having a main clamp piston thereon, a cylinder surroundingsaid main clamp piston, means to supply air under pressure beneath saidpiston to elevate said table to assemble such drag portion with a copeportion and clamp the thus formed core box against a sand blowreservoir, a stop piston surrounding said rod above said main piston,means limiting vertical movement of said stop piston, means operative toenergize said stop piston to drive said main piston downwardly, saidstop piston including a depending shoe operative to engage said mainpiston, and means to hold said main piston against said shoe in suchintermediate position.

6. In a foundry sand forming machine, a large diameter main elevatingpiston and rod adapted to support a sand enclosure, a stop pistonsurrounding said rod and operative to engage said main piston, and meansoperative to pressurize or vent said stop piston thus differentially topressurize said pistons to hold said main piston in an intermediateposition.

7. A foundry sand forming machine as set forth in claim 6 wherein saidlast mentioned means includes means to increase the pressure on saidstop piston with respect to said main piston to push the latterdownwardly to such intermediate position.

8. A foundry sand forming machine as set forth in claim 6 includingmeans to increase the pressure on said main piston with respect to saidstop piston to push the latter upwardly from such intermediate position.

9. In a foundry sand forming machine, a main elevating piston adapted tosupport a sand enclosure on the rod thereof, a stop piston surroundingsaid rod above said main piston and operative to engage the latter, andmeans operative to pressurize said stop piston to provide a forcegreater than that on said main piston to hold the same in anintermediate position.

10. A foundry sand forming machine as set forth in claim 9 wherein suchintermediate position is achieved by moving said main piston upwardly.

11. A foundry sand forming machine as set forth in 1 1 claim whereinsuch intermediate position is achieved by moving said stop pistondownwardly.

12. In a foundry sand forming machine, a main piston and rod adapted tosupport a sand enclosure, a stop piston surrounding said rod adapted toengage said main piston, and means limiting the stroke of said stoppiston to pro vide a releasable abutment for said main piston, said mainand stop pistons comprising oppositely directed single acting pistons.

13. A foundry sand forming machine as set forth in claim 12 including acommon vent between said pistons.

14. In a foundry sand forming machine, a large cylinder, a mainelevating piston adapted to be supported on a large volume of air withinsaid cylinder, a rod extending from said piston and adapted to support afoundry sand forming pattern for vertical movement, a stop ringsurrounding said rod above said piston and adapted to be engagedthereby, means limiting vertical downward movement of said stop ring,means operative to hold said stop ring in such limited lower position toprovide an abutment for said main piston, and means operative to releasesaid stop ring whereby said main piston may continue upwardly.

15. A foundry molding machine comprising a vertically movable tableadapted to support a pattern, a piston rod supporting said table, a mainsqueeze piston thereon, a cylinder surrounding said main squeeze piston,means to supply air under pressure beneath said squeeze piston toelevate said table to assemble such pattern with a flask, a stop pistonsurrounding said rod, means limiting vertical downward movement of saidstop piston, means to supply air under pressure to said stop pistonholding the same down to engage said main squeeze piston and thus holdsuch pattern and flask in an intermediate position to be filled withsand, and means to change the pressures on said main and stop pistons tomove such sand filled flask upwardly from such inter-mediate position tosqueeze the sand therein.

16. A foundry molding machine as set forth in claim 15 wherein said mainand stop pistons are oppositely directed single acting pistons.

17. A foundry molding machine as set forth in claim 16 including acommon intermediate vent for said pistons.

18. A foundry molding machine comprising a vertically movable tableadapted to support a pattern, a piston rod supporting said table, a mainsqueeze piston thereon, a cylinder surrounding said main squeeze piston,means to supply air under pressure beneath said squeeze piston toelevate said table to assemble such pattern with a flask, a stop pistonsurrounding said rod, means limiting vertical downward movement of saidstop piston, means to supply air under pressure to said stop pistonholding the same down to engage said main squeeze piston and thusholdsuch pattern and flask in an intermediate position to be filled'Wllll sand, means to change the pressures on said main and stop pistonsto move such sand filled flask upwardly from such intermediate positionto squeeze the sand therein, said rod being hollow and containing ashockless jolt mechanism vertically movable with said table.

19. A foundry sand forming machine as set forth in claim 14 includingmeans operative to pressurize said stop ring to drive said mainelevating piston downwardly to an intermediate position.

References Cited UNITED STATES PATENTS 787,480 4/ 1905 Tanner 92--622,118,098 5/1938 Merenda 9262 X 2,122,022 6/1938 Campbell 22-26 X2,611,938 9/1952 Hansberg 22,l0

J. SPENCER OVERHOLSER, Primary Examiner.

E. MAR, Assistant Ex'aminer.

6. IN A FOUNDRY SAND FORMING MACHINE, A LARGE DIAMETER MAIN ELEVATINGPISTON AND ROD ADAPTED TO SUPPORT A SAND ENCLOSURE, A STOP PISTONSURROUNDING SAID ROD AND OPERATIVE TO ENGAGE SAID MAIN PISTON, AND MEANSOPERATIVE TO PRESSURIZE OR VENT SAID STOP PISTON THUS DIFFERENTIALLY TOPRESSURIZE SAID PISTONS TO HOLD SAID MAIN PISTON IN AN INTERMEDIATEPOSITION.